Laser annealing apparatus, inspection method of substrate with crystallized film, and manufacturing method of semiconductor device

ABSTRACT

A laser annealing apparatus ( 1 ) according to the embodiment includes: a laser beam source ( 11 ) configured to emit a laser beam (L 1 ) to crystallize an amorphous silicon film ( 101   a ) on a substrate ( 100 ) and to form a poly-silicon film ( 101   b ); a projection lens ( 13 ) configured to condense the laser beam to irradiate a silicon film ( 101 ); a probe beam source configured to emit a probe beam (L 2 ); a photodetector ( 25 ) configured to detect the probe beam (L 3 ) transmitted through the silicon film ( 101 ), a processing apparatus ( 26 ) configured to calculate a standard deviation of detection values of a detection signal output from the photodetector, and to determine a crystalline state of the crystallized film based on the standard deviation.

TECHNICAL FIELD

The present disclosure relates to a laser annealing apparatus, aninspection method of a substrate with crystalized film and amanufacturing method of a semiconductor device.

BACKGROUND ART

Patent Literature 1 discloses a laser annealing apparatus for forming apolysilicon thin film. The laser annealing apparatus in PatentLiterature 1 irradiates a polysilicon thin film with evaluating light toevaluate the crystalline state of the polysilicon thin film. Then, thelaser annealing apparatus detects the irradiation light transmittedthrough the polysilicon thin film. The crystalline state is evaluatedbased on the ratio of the transmission intensity of the irradiationlight to the light intensity of reference light which is emitted fromthe same light source and is not transmitted through the polysiliconthin film.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent No. 2916452

SUMMARY OF INVENTION Technical Problem

However, the laser annealing apparatus in Patent Literature 1 cannotproperly evaluate a crystalline state.

Other problems and novel features will be clarified from the descriptionof this specification and the attached drawings.

Solution to Problem

According to an embodiment, an inspection method of a substrate with acrystalized film, the method includes the steps of: (C) detecting, by aphotodetector, the probe beam transmitted through the crystallized film;(D) changing an irradiation position of the probe beam on thecrystallized film to acquire a plurality of detection values of adetection signal from the photodetector; and (E) determining, based on astandard deviation of the plurality of detection values, a crystallinestate of the crystallized film.

According to an embodiment, manufacturing method of a semiconductordevice, the method includes the steps of: (b) irradiating the amorphousfilm with a laser beam to crystallize the amorphous film and to form acrystallized film; (c) irradiating the crystallized film with a probebeam; (d) detecting, by a photodetector, the probe beam transmittedthrough the crystallized film; (e) changing an irradiation position ofthe probe beam on the crystallized film to acquire a plurality ofdetection values of a detection signal output from the photodetector;and (f) determining, based on a standard deviation of the plurality ofdetection values, a crystalline state of the crystallized film.

According to an embodiment, a laser annealing apparatus includes: alaser beam source configured to emit a laser beam to crystallize anamorphous film over a substrate and to form a crystallized film; a probebeam source configured to emit a probe beam; a photodetector configuredto detect the probe beam transmitted through the crystallized film; anda processing unit configured to change an irradiation position of theprobe beam on the substrate, to calculate a standard deviation ofdetection values of a detection signal output from the photodetector,and to determine a crystalline state of the crystallized film based onthe standard deviation.

According to an embodiment, a laser annealing apparatus includes: astage configured to convey the substrate; a probe beam source configuredto emit a probe beam that enters the substrate outside of the stage; anda photodetector configured to detect the probe beam transmitted throughthe crystallized film outside the stage during a conveying robot takesout the substrate from the stage.

Advantageous Effects of Invention

According to the embodiment, it is possible to properly evaluate thecrystalline state of a crystallized film.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing an optical system of a laser annealingapparatus according to the present embodiment.

FIG. 2 is a perspective view for explaining a laser beam and a probebeam that enter a substrate in the laser annealing apparatus.

FIG. 3 is a diagram for explaining a laser beam and a probe beam thatenter a substrate.

FIG. 4 is a diagram showing a probe beam that enters a substrate.

FIG. 5 is a flowchart showing an inspection method according to anembodiment.

FIG. 6 is a graph showing detection values in a condition-settingsubstrate.

FIG. 7 is a graph showing the average values and the standard deviationsof detection values in a condition-setting substrate.

FIG. 8 is a diagram showing the captured images and the standarddeviations of three substrates.

FIG. 9 is a flowchart showing a method for forming a polysilicon filmusing an ELA apparatus according to the present embodiment.

FIG. 10 is a diagram showing an apparatus layout including the ELAapparatus according to the present embodiment.

FIG. 11 is a flowchart showing a method for forming a polysilicon filmusing an ELA apparatus according to a comparison example.

FIG. 12 is a diagram showing an apparatus layout including the ELAapparatus according to the comparison example.

FIG. 13 is a plan view schematically showing a configuration of an ELAapparatus according to a second embodiment.

FIG. 14 is a side view schematically showing the configuration of theELA apparatus according to the second embodiment.

FIG. 15 is a diagram showing a configuration for a laser beam and aprobe beam to enter a substrate from the same side.

FIG. 16 is a cross-sectional view of a simplified configuration of anorganic EL display.

FIG. 17 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

FIG. 18 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

FIG. 19 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

FIG. 20 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

[FIG. 21] FIG. 20 is a cross-sectional view showing a process in amanufacturing method of a semiconductor device according to the presentembodiment.

FIG. 22 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

FIG. 23 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

FIG. 24 is a cross-sectional view showing a process in a manufacturingmethod of a semiconductor device according to the present embodiment.

FIG. 25 is a flowchart showing a method for determining the optimizedenergy density of a laser beam in an inspection method according to thepresent embodiment.

FIG. 26 is a diagram for explaining the region of the substrate in theflowchart shown in FIG. 25.

FIG. 27 is a side view schematically showing the configuration of theELA apparatus according to a third embodiment.

FIG. 28 is a plan view schematically showing a configuration of an ELAapparatus according to the third embodiment.

FIG. 29 is a diagram showing the size of a probe beam according to a Zposition.

FIG. 30 is a diagram showing an example of an optical system for a probebeam in an ELA apparatus.

FIG. 31 is a diagram showing an example of an optical system for a probebeam in an ELA apparatus.

FIG. 32 is a diagram showing an example of an optical system for a probebeam in an ELA apparatus.

FIG. 33 is a graph showing a measurement result of a probe beam.

DESCRIPTION OF EMBODIMENTS First Embodiment

A laser annealing apparatus according to the present embodiment is, forexample, an excimer laser anneal (ELA) apparatus that forms lowtemperature poly-silicon (LTPS) films. Hereinafter, a laser annealingapparatus, and an inspection method and a manufacturing method of asemiconductor device according to the present embodiment are describedwith reference to the drawings.

(Optical System of ELA Apparatus)

A configuration of an ELA apparatus 1 according to the presentembodiment is described with reference to FIG. 1. FIG. 1 is a diagramschematically showing an optical system of the ELA apparatus 1. The ELAapparatus 1 irradiates a silicon film 101 formed on a substrate 100 witha laser beam L1. This converts an amorphous silicon film (a-Si film) 101into a polysilicon film (p-Si film) 101. The substrate 100 is, forexample, a transparent substrate such as a glass substrate.

Note that, an XYZ three-dimensional orthogonal coordinate system isshown in FIG. 1 to clarify the description. The Z direction is thevertical direction and perpendicular to the substrate 100. The XY planeis parallel to the surface of the substrate 100 on which the siliconfilm 101 is formed. The X direction is the longitudinal direction of therectangular substrate 100, and the Y direction is the latitudinaldirection of the substrate 100. In the ELA apparatus 1, the silicon film101 is irradiated with the laser beam L1 while the substrate 100 isbeing conveyed in the +X direction with a conveyance mechanism (notshown) such as a stage. With regard to the silicon film 101 in FIG. 1,the silicon film 101 before the irradiation with the laser beam L1 isreferred to as an amorphous silicon film 101 a, and the silicon film 101after the irradiation with the laser beam L1 is referred to as apolysilicon film 101 b.

The ELA apparatus 1 includes an annealing optical system 10, anillumination optical system 20, and a detection optical system 30. Theannealing optical system 10 irradiates the silicon film 101 with thelaser beam L1 for crystallizing the amorphous silicon film 101 a. Theillumination optical system 20 and the detection optical system 30evaluate ununiformity in the crystalline state of the substrate 100.

Specifically, the ELA apparatus 1 includes a laser beam source 11, amirror 12, a projection lens 13, a probe beam source 21, a mirror 22, alens 23, a condenser lens 24, a photodetector 25, and a processingapparatus 26.

First, the annealing optical system 10 that irradiates the silicon film101 with the laser beam L1 is described. The annealing optical system 10is disposed above the substrate 100 (at the +Z side). The laser beamsource 11 is, for example, an excimer laser beam source that emits anexcimer laser beam having a center wavelength of 308 nm. The laser beamsource 11 emits a pulsed laser beam L1. The laser beam source 11 emitsthe laser beam L1 toward the mirror 12.

The mirror 12 and the projection lens 13 are disposed above thesubstrate 100. The mirror 12 is a dichroic mirror that selectivelytransmits light according to, for example, a wavelength. The mirror 12reflects the laser beam L1.

The laser beam L1 is reflected by the mirror 12 and enters theprojection lens 13. The projection lens 13 includes a plurality of lensfor projecting the laser beam L1 on the substrate 100, that is, on thesilicon film 101.

The projection lens 13 condenses the laser beam L1 on the substrate 100.Here, the shape of an irradiation region P1 of the laser beam L1 on thesubstrate 100 is described with reference to FIG. 2. The laser beam L1forms a linear irradiation region P1 along the Y direction on thesubstrate 100. That is, the laser beam L1 is a line beam having itslongitudinal direction in the Y direction on the substrate 100. Thesilicon film 101 is irradiated with the laser beam L1 while thesubstrate 100 is being conveyed in the +X direction. Thus, a belt-shapedregion having the length of the irradiation region P1 in the Y directionas its width can be irradiated with the laser beam L1.

Next, the illumination optical system 20 that irradiates the substrate100 with a probe beam L2 is described with reference to FIG. 1. Theillumination optical system 20 is disposed under the substrate 100 (atthe −Z side). The probe beam source 21 emits a probe beam L2 having adifferent wavelength from the laser beam L1. For example, a continuouswave (CW) semiconductor laser beam source or the like can be used as theprobe beam source 21. The center wavelength of the probe beam L2 is, forexample, 401 nm. The wavelength of the probe beam L2 is preferably awavelength with a low absorption rate at the silicon film 101. Thus, itis preferable that a laser beam source, a light emitting diode (LED)light source, or the like that emits monochromatic light is used as theprobe beam source 21.

The probe beam source 21 emits the probe beam L2 toward the mirror 22.The mirror 22 reflects the probe beam L2 toward the lens 23. The lens 23condenses the probe beam L2 on the silicon film 101. As shown in FIG. 2,a cylindrical lens can be used as the lens 23. Accordingly, the probebeam L2 forms a linear illumination region P2 along the Y direction onthe substrate 100 (the silicon film 101). That is, the probe beam L2 isa line beam having its longitudinal direction in the Y direction on thesubstrate 100. In addition, the length of the illumination region P2 inthe Y direction is shorter than the irradiation region P1.

The illumination region P2 of the probe beam L2 is disposed at the +Xside compared to the irradiation region P1 of the laser beam L1. Thatis, the probe beam L2 enters the substrate 100 at an upper stream sidein the conveying direction of the substrate 100 than the irradiationregion P1 of the laser beam L1. Accordingly, the crystallizedpolysilicon film 101 b is irradiated with the probe beam L2 as shown inFIG. 1.

Next, the detection optical system 30 that guides a probe beam L3transmitted through the silicon film 101 to the photodetector 25 isdescribed. The detection optical system 30 is disposed above thesubstrate 100. Note that, FIG. 1 shows the probe beam transmittedthrough the silicon film 101 as the probe beam L3. The transmittance ofthe silicon film 101 to a probe beam varies according to the crystallinestate of silicon.

The probe beam L3 transmitted through the silicon film 101 enters theprojection lens 13. The probe beam L3 refracted by the projection lens13 enters the mirror 12. Note that, the mirror 12 is a dichroic mirrorthat transmits or reflects light according to a wavelength as describedabove. The mirror 12 transmits the probe beam L3 having the wavelengthof 401 nm and reflects the laser beam L1 having the wavelength of 308nm. Thus, the probe beam L3 is branched from the optical path of thelaser beam L1. The mirror 12 serves as a light branching means forbranching the optical path of the laser beam L1 and the optical path ofthe probe beam L3 according to a wavelength.

The probe beam L3 having passed through the mirror 12 enters thecondenser lens 24. The condenser lens 24 condenses the probe beam L3 onthe light-receiving surface of the photodetector 25. The photodetector25 is, for example, a photo diode and detects the probe beam L3. Thephotodetector 25 outputs a detection signal according to the detectionlight amount of the probe beam L3 to the processing apparatus 26. Thedetection value of the detection signal corresponds to the transmittanceof the silicon film 101. In addition, since the substrate 100 isconveyed in the +X direction at a constant speed, the photodetector 25detects the profile of the detection light amount in the X direction(that is, the transmittance of the silicon film 101).

The processing apparatus 26 is an operation unit that performspredetermined operation to the detection value of the detection signal.Note that, the processing apparatus 26 may includes an A/D converterthat A/D-converts an analogue detection signal into a digital detectionvalue. Alternatively, the photodetector 25 may includes an A/D converterthat A/D-converts an analogue detection signal into a digital detectionvalue.

While scanning the substrate 100 in the +X direction, the photodetector25 detects the probe beam L3. Thus, the processing apparatus 26 acquiresa plurality of detection values according to the sampling rate of thephotodetector 25 or the A/D converter. The processing apparatus 26includes a memory that stores the detection values. Since the substrate100 is scanned in the +X direction at a constant speed, the detectionvalues indicate the profile of the transmittance in the X direction. Ifthe crystalline state of the silicon film 101 is ununiform, differentdetection values according to the illumination positions are acquired.If the crystalline state of the silicon film 101 is uniform, thedetection values are substantially the same value.

The processing apparatus 26 determines the quality of the substrate 100based on the standard deviation of the detection values. That is, whenthe standard deviation is less than a preset threshold, the processingapparatus 26 determines that the ununiformity in the crystalline stateis small. In this case, the processing apparatus 26 that the polysiliconfilm 101 b is formed uniformly and that the substrate 100 isnon-defective. On the other hand, when the standard deviation is equalto or greater than the preset threshold, the processing apparatus 26determines that the ununiformity in the crystalline state is large. Inthis case, the processing apparatus 26 determines that the polysiliconfilm with large ununiformity is formed and that the substrate 100 isdefective. The processing of the processing apparatus 26 is to bedescribed later.

With reference to FIGS. 3 and 4, the illumination region P2 of the probebeam L2 on the substrate 100 is described. FIG. 3 is an XY plan viewshowing examples of the illumination region P2 of the probe beam L2 andthe irradiation region P1 of the laser beam L1. FIG. 4 shows the probebeam L2 measured by a beam profiler.

As shown in FIG. 3, the width of the irradiation region P1 in the Xdirection is 400 μm. In addition, a gap of 100 μm is provided betweenthe irradiation region P1 and the illumination region P2 in the Xdirection. The length of the irradiation region P1 in the Y direction islonger than the length of the illumination region P2. As shown in FIG.4, the length of the illumination region P2 in the Y direction is 6 mm.The maximum width of the illumination region P2 in the X direction is 17Note that, when the irradiation region P1 is smaller than the size ofthe substrate 100 in the Y direction, the substrate 100 is moved in theY direction to perform annealing treatment. Accordingly, a silicon film100 is crystallized on the entire substrate 100.

Here, it is assumed that the conveyance speed of the substrate 100 inthe X direction is 12 mm/sec. Furthermore, it is assumed that thecondensed size of the illumination region P2 is 17 μm, and that themeasurement overlap is set to 50% (=8.5 μm). The sampling rate requiredin this case is 12000/8.5=1.411 kHz. Note that, the measurement overlapdefines the size of the overlapped illumination region P2 between thetwo consecutive detection values. That is, the region overlapped by 8.5μm is irradiated with the illumination region P2 corresponding to thefirst detection value and the illumination region P2 corresponding tothe second detection value.

Next, an inspection method according to the present embodiment isdescribed with reference to FIG. 5. FIG. 5 is a flowchart showing theinspection method according to the present embodiment.

First, when annealing treatment is performed to the silicon film 101,the processing apparatus 26 acquires n numbers of detection values V₁,V₂, . . . , V_(n) (S11). Here, n is an integer of 2 or more. As theillumination position of the probe beam L2 is changed in the Xdirection, the detection values V₁ to V_(n) are detected. For example,the detection value when the illumination position on the substrate 100in the X direction is X₁ is V₁, and the detection value when theillumination position on the substrate 100 in the X direction is X₂ isV₂. The detection value when the illumination position on the substrate100 in the X direction is X_(n) is V_(n). In this manner, thephotodetector 25 detects a detection value according to an illuminationposition in the X direction. As the illumination position onto thesubstrate 100 is changed by the substrate conveyance, the processingapparatus 26 acquires the detection values V₁ to V_(n).

Then, the processing apparatus 26 calculates an average valueV_(average) and a standard deviation σ of the detection values V₁ toV_(n) (S12). Specifically, a processor or an operation circuit providedto the processing apparatus 26 calculates the average value V_(average)and the standard deviation σ based on the expressions shown in FIG. 5.

The processing apparatus 26 determines whether the calculated standarddeviation σ is less than a threshold σ_(α) (S13). That is, theprocessing apparatus 26 compares the standard deviation σ with thepreset threshold σ_(α). Then, when the standard deviation σ is less thanthe threshold σ_(α) (YES in S13), the processing apparatus 26 determinesthe substrate 100 to be non-defective, and the treatment is terminated.On the other hand, when the standard deviation σ is equal to or greaterthan the threshold σ_(α) (NO in S13), the processing apparatus 26determines the substrate 100 to be defective, and returns to theannealing treatment. Accordingly, re-annealing treatment is performed tothe defective substrate 100.

In the re-annealing treatment, the entire surface of the substrate 100is irradiated with the laser beam L1 similarly to the first annealingtreatment. In the re-annealing treatment, the substrate 100 isirradiated with the laser beam L1 having a weaker irradiation intensitythan that in the first annealing treatment. The portion where theirradiation light amount of the laser beam L1 has been insufficient tobe adequately crystallized can be certainly crystallized. In addition,the photodetector 25 may detect the probe beam L3, and the processingapparatus 26 may determine the crystalline state similarly in there-annealing treatment.

Furthermore, the substrate 100 may be partially irradiated with thelaser beam L1 in the re-annealing treatment. It is thereby possible toshorten the time required for the re-annealing treatment. For example,the measurement range is divided into ten, and the processing apparatus26 calculates ten standard deviations σ₁ to σ₁₀. Then, the portionshaving large standard deviations among the standard deviations σ₁ to σ₁₀may be irradiated with the laser beam L1. For this reason, theprocessing apparatus 26 compares each of the standard deviations σ₁ toσ₁₀ with the threshold σ_(α) to obtain the portions having standarddeviations greater than the threshold σ_(α). Then, the portions havingthe standard deviations greater than the threshold σ_(α) are irradiatedwith the laser beam L1. In other words, the portions having the standarddeviations less than the threshold σ_(α) are not irradiated with thelaser beam L1. It is obvious that the number of divisions of thesubstrate 100 is not limited to ten, and the number is only required tobe two or more.

In the present embodiment, the quality determination based on theaverage value V_(average) is performed in S13 in addition to the qualitydetermination based on the standard deviation σ. That is, the averagevalue is added to the evaluation items as well as the standarddeviation. Then, when either of the standard deviation or the averagevalue does not meet the criterion, the processing apparatus 26determines the substrate 100 to be defective. Note that, the qualitydetermination based on the average value V_(average) may not beperformed. In this case, the processing apparatus 26 is only required tocalculate the standard deviation σ without calculating the average valueV_(average) in step S12.

Specifically, it is determined whether the average value V_(average) isless than a threshold V_(α) (S13). That is, the processing apparatus 26compares the average value V_(average) with the preset threshold V_(α).Then, when the average value V_(average) is greater than the thresholdV_(α) (YES in S13), the processing apparatus 26 determines the substrate100 to be non-defective and terminates the treatment. On the other hand,when the average value V_(average) is equal to or less than thethreshold V_(α) (YES in S13), the processing apparatus 26 determines thesubstrate 100 to be defective and returns to the annealing treatment. Inthis manner, by performing the quality determination based on both ofthe standard deviation σ and the average value V_(average), it ispossible to more properly evaluate the crystalline state. Thus, it ispossible to improve the accuracy of the quality determination. Then, thelaser annealing apparatus 1 performs re-annealing treatment to thesubstrate 100 determined to be defective. Accordingly, it is possible tocertainly crystallize the portion where the irradiation light amount ofthe laser beam L1 has been insufficient to be adequately crystallized.Thus, it is possible to improve the ununiformity in the crystallinestate.

In this manner, the photodetector 25 detects the probe beam L3transmitted through the substrate 100 in the present embodiment. Sincethe probe beam L3 is detected at different illumination positions by thephotodetector 25, the processing apparatus 26 acquires a plurality ofdetection values. The processing apparatus 26 performs the qualitydetermination based on the standard deviation of the detection values.It is thereby possible to properly evaluate ununiformity in thepolysilicon film 101 b. Thus, it is possible to further improve theaccuracy of the quality determination. Especially when the laser beam L1is a linear pulsed laser beam, stripes of light and darkness along theline (also referred to as shot unevenness) can appear on the siliconfilm 101. It is possible for the ELA apparatus 1 according to thepresent embodiment to reduce the shot unevenness.

In the present embodiment, by adding not only the standard deviation σof the detection values but also the average value V_(average) to theevaluation items, it is possible to further improve the accuracy of thequality determination. In addition, the re-annealing treatment isperformed to the substrate 100 determined to be defective. It ispossible to certainly crystallize the portion where the irradiationlight amount of the laser beam L1 has been insufficient to be adequatelycrystallized. Thus, it is possible to improve the yield and to increasethe productivity.

Furthermore, while a substrate is being conveyed by a stage or the like,the substrate 100 is irradiated simultaneously with the laser beam L1and the probe beam L2. It is thereby possible to detect the probe beamL3 transmitted through the silicon film 101 during laser annealing.Thus, it is possible to determine whether the state of the surface ofthe silicon film 101 is optimal in a short time.

In the present embodiment, the illumination region P2 of the probe beamL2 is disposed in the vicinity of the irradiation region P1 of the laserbeam L1. Accordingly, it is possible to evaluate the crystalline stateof the silicon film 101 immediately after being crystallized. Thus, itis possible to evaluate ununiformity in the crystalline state of thesilicon film 101 substantially on time and to improve the accuracy ofthe quality determination.

In addition, the photodetector 25 detects the probe beam having passedthrough the projection lens 13 in order to bring the illumination regionP2 of the probe beam L2 closer to the irradiation region P1 of the laserbeam L1. In other words, the projection lens 13 is disposed in theoptical path from the probe beam source 21 to the photodetector 25. Theprojection lens 13 is shared by the annealing optical system 10 and theillumination optical system 20. Accordingly, it is possible to bring theillumination region P2 closer to the irradiation region P1 on thesubstrate 100.

In the present embodiment, the substrate 100 is irradiated with thelinear illumination region P2. Thus, it is possible to reduce theinfluence of small dirt, dust, or the like. For example, in the case ofthe irradiation with a point-like illumination region, if dirt or thelike is attached to the illumination region, the transmittance isgreatly lowered. In this case, the detection value at the portion towhich the dirt or the like is attached is greatly lowered, and thestandard deviation becomes larger. On the other hand, by the irradiationwith the linear illumination region P2 as described in the presentembodiment, it is possible to reduce the influence of small dirt or thelike. That is, since the region having a wide width in the Y directionis irradiated, it is possible to improve the accuracy of the qualitydetermination compared with the irradiation with a point-likeillumination region. Furthermore, since the illumination region P2 isparallel to the linear irradiation region P1, it is possible to properlyevaluate shot unevenness which is stripes of light and darkness alongthe Y direction.

In the present embodiment, the condenser lens 24 is disposed in front ofthe photodetector 25. The condenser lens 24 condenses the probe beam L3on the light-receiving surface of the photodetector 25. That is, theprobe beam L3 forms a point-like spot on the light-receiving surface ofthe photodetector 25. Thus, it is possible to use a diode having a smalllight-receiving region as the photodetector 25. Accordingly, it is notnecessary to use a camera in which light-receiving pixels are arrangedin an array or the like as the photodetector 25. Furthermore, it is outnecessary to perform image processing to images by the camera. Thus, itis possible to simplify the configuration and the processing of theapparatus.

(Measurement Result)

FIG. 6 shows a measurement result of the probe beam L3. FIG. 6 is agraph showing a measurement result in a condition-setting substrate. Thegraph shows the measurement result of the probe beam L3 when theirradiation intensity of the laser beam L1 to one substrate 100 ischanged. Specifically, the substrate 100 is divided into 21 regions T80to T100 as shown in FIG. 6, and the irradiation intensity of the laserbeam L1 is changed at each region. The irradiation intensity isgradually increased from the region T80 toward the region T100.Specifically, the numeral representing each region means the irradiationintensity when the irradiation intensity at the region T100 is set to100. For example, the region T80 means the 80% irradiation intensity ofthe region T100, and the region T81 means the 81% irradiation intensityof the region T100. Note that, the irradiation intensity at each regionis constant. The vertical axis indicates a detection value of adetection signal of the photodetector 25. The detection value in thisgraph corresponds to the voltage [V] of the detection signal output fromthe photodetector 25.

FIG. 7 shows the average value and the standard deviation σ of thedetection values V at each region. It is assumed that the characteristicof the silicon film 101 is more excellent as the detection values V aresmaller. In this case, the region having the smallest average value isthe region T95, but the region having the smallest standard deviation σis the region T85. Thus, the irradiation intensity at the region T85 canbe the optimized irradiation intensity. In other words, the averagevalue is small but the variation of the detection value is large at theregion T95, and the standard deviation is large. For this reason,ununiformity in the crystalline state is increased, and a defective ratecan be increased. By performing the annealing treatment using the laserbeam L1 having the irradiation intensity at the region T85, it ispossible to form the polysilicon film 101 b having a uniform crystallinestate.

FIG. 8 is a diagram showing images of the substrate 100 captured by acamera and measurement results by the photodetector 25. FIG. 8 showsthree substrate 100 as substrates I to III, and the irradiationintensity of the laser beam L1 to each substrate is changed. Inaddition, each of the substrates I to III is irradiated with the laserbeam L1 having the constant irradiation intensity. The captured imagesare shown at the upper part of FIG. 8, and the detection values (voltagevalues) are shown at the lower part. FIG. 8 shows that the detectionvalues vary in the substrates I and III the images of which have largeuneven brightness. On the other hand, the variation in the detectionvalues is small in the substrate II the image of which has small unevenbrightness. In this manner, by performing inspection based on thestandard deviation of the detection values, it is possible to improvethe accuracy of the quality determination.

(Method for Forming Polysilicon Film)

In the present embodiment, since the ELA apparatus 1 has a function ofquality determination, it is possible to further increase theproductivity. This point is described with reference to FIGS. 9 and 10.FIG. 9 is a flowchart showing a method for forming a polysilicon filmusing the ELA apparatus 1. More specifically, FIG. 9 shows a formingmethod when a substrate is determined to be defective by the inspectionmethod according to the present embodiment. FIG. 10 is a diagram showingan apparatus layout for the ELA apparatus 1 and a cleaning apparatus 3in a manufacturing factory.

First, the ELA apparatus 1 performs the annealing treatment and thequality determination (S101). Specifically, a transfer robot 4 takes outthe substrate 100 with an amorphous silicon film cleaned by the cleaningapparatus 3 from a cassette 5. Then, the transfer robot 4 carries thesubstrate 100 in the ELA apparatus 1. Note that, the transfer robot 4includes two hands and can hold the substrate 100 to be carried in eachapparatus and the substrate 100 to be carried out of each apparatus atthe same time.

Then, the substrate 100 is irradiated with the laser beam L1 and theprobe beam L2 while the substrate 100 is being conveyed as shown in FIG.1 and the like. For example, by driving a stage or the like to conveythe substrate 100, the annealing treatment and the quality determinationare performed. Since the substrate 100 is irradiated simultaneously withthe laser beam L1 and the probe beam L2, the annealing treatment and thequality determination are finished substantially at the same time. Sincethe photodetector 25 detects the probe beam L3 while the substrate 100is being conveyed, the processing apparatus 26 acquires a plurality ofdetection values. Then, when the processing apparatus 26 determines thesubstrate 100 to be defective based on the standard deviation σ of thedetection values, the re-annealing treatment is performed (S102). Here,steps S101 and S102 are performed in the same ELA apparatus 1. That is,it is possible to perform steps S101 and S102 without carrying thesubstrate 100 out of the ELA apparatus 1.

Next, a method for forming a polysilicon film using an ELA apparatusaccording to a comparison example is described with reference to FIGS.11 and 12. FIG. 11 is a flowchart showing a method for forming apolysilicon film using an ELA apparatus 201 according to a comparisonexample. FIG. 12 is a diagram showing a layout for the ELA apparatus201, a cleaning apparatus 203, and an inspection apparatus 202 in amanufacturing factory. Note that, the ELA apparatus 201 according thecomparison example does not have a function of quality determination.Thus, the inspection apparatus 202 is disposed in the vicinity of theELA apparatus 201 and the cleaning apparatus 203. The inspectionapparatus 202 performs the quality determination for the substrate 100.

First, the ELA apparatus 201 performs laser annealing treatment (S201).Specifically, a transfer robot 204 takes out the substrate 100 with anamorphous silicon film cleaned by the cleaning apparatus 203 from acassette 205. Then, the transfer robot 204 carries the substrate 100 inthe ELA apparatus 201. Then, the ELA apparatus 201 performs annealingtreatment.

When the annealing treatment is finished, the transfer robot 204 carriesthe substrate 100 subjected to the annealing treatment out of the ELAapparatus (S202). When a mobile robot 204 that has carried the substrate100 out moves before the inspection apparatus is carried in (S204), thetransfer robot 204 carries the substrate 100 in the inspection apparatus202 (S205).

The inspection apparatus 202 performs the quality determination for thecarried-in substrate 100 (S206). Here, an example in which the substrate100 is determined to be defective is described. The transfer robot 204carries the substrate 100 out of the inspection apparatus 202 (S207).When the transfer robot 204 that has carried the substrate 100 out movesbefore the ELA apparatus 201 is carried in (S209), the transfer robot204 carries the substrate 100 in the ELA apparatus 201 (S210). Then, theELA apparatus 201 performs re-annealing treatment to the substrate 100determined to be defective (S211).

In this manner, since the ELA apparatus 201 according to the comparisonexample does not have a function of quality determination, the number oftimes of carrying-in and carrying-out of the substrate 100 is increased.That is, the substrate 100 is required to be carried in and carried outof the inspection apparatus 202. This makes tact time longer, and it isdifficult to improve the productivity. In addition, a cleaning processby the cleaning apparatus 203 can be required between the qualitydetermination process by the inspection apparatus 202 (S206) and there-annealing treatment S211 by the ELA apparatus 201. In this case, thenumber of times of carrying-in and carrying-out of the substrate 100 isfurther increased, and the productivity is lowered.

In other words, it is possible for the ELA apparatus 1 according to thepresent embodiment to manufacture the substrate 100 with a polysiliconfilm with high productivity. That is, since the number of times ofcarrying-in and carrying-out of the substrate 100 is reduced, it ispossible to finish the treatment in a short time. Furthermore, since theannealing treatment and the quality determination are performed in thesame ELA apparatus 1, it is not necessary to perform a cleaning processbetween the quality determination and the re-annealing treatment.Accordingly, it is possible to reduce the number of times of carrying-inand carrying-out of the substrate 100 and to improve the productivity.In addition, it is possible to evaluate the polysilicon film 101 bimmediately after the irradiation with the laser beam L1. Thus, it ispossible to feed back the condition, such as transmittance, for the nextsubstrate 100 and to perform laser irradiation under an appropriatecondition.

Second Embodiment

An ELA apparatus 40 according to the present embodiment is describedwith reference to FIGS. 13 and 14. FIG. 13 is a plan view schematicallyshowing a configuration of the ELA apparatus 40. FIG. 14 is a side viewschematically showing the configuration of the ELA apparatus 40. Theconfiguration of the apparatus is appropriately simplified in FIGS. 13and 14. In the present embodiment, a function of quality determinationis added to the ELA apparatus 40 provided with a gas-floating unit.

The ELA apparatus 40 includes a treatment room 41, a continuousconveying path 42, gas-floating units 43 a and 43 b, a suction part 44,and an opening 45. The treatment room 41 includes a carrying-in port 41a and a carrying-out port 41 b. The ELA apparatus 40 includes, similarlyto the first embodiment, an annealing optical system 10, an illuminationoptical system 20, and a detection optical system 30.

The ELA apparatus 40 according to the present embodiment is providedwith the gas-floating units 43 a and 43 b that float a substrate 100 inthe treatment room 41 in which annealing treatment is performed. Notethat, the basic configuration except for the gas-floating units 43 a and43 b is similar to the ELA apparatus 1 described in the firstembodiment, and the description is appropriately omitted. For example,the optical system of the ELA apparatus 40 according to the presentembodiment is substantially similar to that of the ELA apparatus 1according to the first embodiment. However, a probe beam L3 enters acondenser lens 24 without passing through a mirror 12. In this case, areflex mirror that reflects almost all incident light can be used as themirror 12 instead of a dichroic mirror.

The treatment room 41 of the ELA apparatus 40 has arectangular-parallelepiped wall part. The carrying-in port 41 a (−Xside) and the carrying-out port 41 b (+X side) are provided on the wallsfacing in the longitudinal direction (the X direction) of the treatmentroom 41. Each of the carrying-in port 41 a and the carrying-out port 41b may be opened or have an openable structure. The openable structurecan be a simple sealing structure. Note that, the setting positions ofthe carrying-in port 41 a and the carrying-out port 41 b are onlyrequired to be along the conveying direction, and not limited tospecific positions.

In the treatment room 41, the continuous conveying path 42 is providedfrom the carrying-in port 41 a to the carrying-out port 41 b. Thegas-floating units 43 a and 43 b are disposed at the continuousconveying path 42. The gas-floating unit 43 a is disposed at thecarrying-in port 41 a side, and the gas-floating unit 43 b is disposedat the carrying-out port 41 b side. The opening 45 is provided betweenthe gas-floating unit 43 a and the gas-floating unit 43 b. The opening45 corresponds to an irradiation region P1 at which laser annealing isperformed.

The gas-floating units 43 a and 43 b are floating stages that jet gasupward from below, and float and support the substrate 100 overthemselves. Note that, the gas-floating units 43 a and 43 b each have aplurality of jetting points (not shown) to adjust the posture andbending of the substrate 100.

As shown in FIG. 14, the part at which the gas-floating unit 43 a isprovided in the continuous conveying path 42 is referred to as acarrying-in conveying path 42 a, and the part at which the gas-floatingunit 43 b is provided is referred to as a carrying-out conveying path 42b. In addition, the part corresponding to the opening 45 in thecontinuous conveying path 42 is referred to as an irradiation-regionconveying path 42 c.

The suction part 44 sucks the end portion of the substrate 100. Thesuction part 44 is moved along a guide rail (not shown) in the Xdirection while the suction part 44 is sucking the substrate 100. It isthereby possible to covey the substrate 100 in the +X direction.

The substrate 100 carried in from the carrying-in port 41 a is conveyedin the order of the carrying-in conveying path 42 a, theirradiation-region conveying path 42 c, and the carrying-out conveyingpath 42 b. Then, when conveyed to the end of the carrying-out conveyingpath 42 b, the substrate 100 is carried out of the carrying-out port 41b. Specifically, the substrate 100 carried in from the carrying-in port41 a is floated by the gas from the gas-floating unit 43 a. A floatingsubstrate 1000 is conveyed in the +X direction (for example, a substrate100 a in FIG. 14). Then, when the substrate 100 reaches anillumination-region conveying path 42 c, the annealing treatment anddetection of a probe beam are performed (for example, a substrate 100 bin FIG. 14).

At this time, the substrate 100 is irradiated with a laser beam L1 and aprobe beam L2 at the opening 45 in the irradiation-region conveying path42 c. Thus, the illumination optical system 20 is disposed so that theprobe beam L2 passes through the opening 45. For example, a lens 23 isdisposed directly under the opening 45. In this manner, the probe beamL2 passes through the opening 45 disposed between the gas-floating unit43 a and the gas-floating unit 43 b. That is, an illumination region P2of the probe beam L2 is positioned in the irradiation-region conveyingpath 42 c.

Then, the substrate 100 reaches the carrying-out conveying path 42 b,the substrate 100 is floated by the gas from both of the gas-floatingunit 43 a and the gas-floating unit 43 b. When the end of the substrate100 passes the carrying-in conveying path 42 a, the substrate 100 isfloated by the gas from the gas-floating unit 43 b (for example, asubstrate 100 c in FIG. 14).

An inspection method according to the present embodiment is suitable forthe ELA apparatus 40 including a plurality of gas-floating units of thegas-floating units 43 a and 43 b. For example, the opening 45 isnormally provided over the entire substrate 100 in the Y direction (seeFIG. 13). Thus, it is possible for the ELA apparatus 40 according to thepresent embodiment to form the illumination region P2 at an arbitraryposition in the Y direction. Accordingly, it is possible to form theillumination region P2 at, for example, the center of the substrate 100in the Y direction. Thus, it is possible to evaluate the crystallinestate at the center of the substrate 100 in the Y direction and toimprove the accuracy of the quality determination.

Note that, the illumination optical system 20 is disposed under thesubstrate 100, and the detection optical system 30 is disposed above thesubstrate 100 in the first and second embodiments, but the positions ofthe illumination optical system 20 and the detection optical system 30may be inverted. That is, the illumination optical system 20 can bedisposed above the substrate 100, and the detection optical system 30can be disposed under the substrate 100. In this case, the lens 23 isdisposed at the +Z side of the substrate 100 as shown in FIG. 15. Insecond embodiment, the probe beam transmitted through the substrate 100passes through the opening 45. In addition, when the illuminationoptical system 20 is disposed above the substrate 100 and the detectionoptical system 30 is disposed under the substrate 100, the probe beam L2may be condensed with a lens different from the projection lens 13.

(Organic EL Display)

A semiconductor device having the above polysilicon film is suitable fora thin film transistor (TFT) array substrate used for an organic electroluminescence (EL) display. That is, the polysilicon film is used as asemiconductor layer having a source region, a channel region, and adrain region of a TFT.

Hereinafter, a case in which a semiconductor device according to thepresent embodiment is used for an organic EL display is described. FIG.16 is a cross section of a pixel circuit of the organic EL display whichis illustrated in a simplified manner. The organic EL display device 300shown in FIG. 16 is an active-matrix-type display device in which a TFTis disposed in each pixel PX.

The organic EL display device 300 includes a substrate 310, a TFT layer311, an organic layer 312, a color filter layer 313, and a sealingsubstrate 314. FIG. 14 shows a top-emission-type organic EL displaydevice, in which the side of the sealing substrate 314 is located on theviewing side. Note that the following description is given to show anexample of a configuration of an organic EL display device and thisembodiment is not limited to the below-described configuration. Forexample, a semiconductor device according to this embodiment may be usedfor a bottom-emission-type organic EL display device.

The substrate 310 is a glass substrate or a metal substrate. The TFTlayer 311 is provided on the substrate 310. The TFT layer 311 includesTFTs 311 a disposed in the respective pixels PX. Further, the TFT layer311 includes wiring lines (not shown) connected to the TFTs 311 a, andthe like. The TFTs 311 a, the wiring lines, and the like constitutepixel circuits.

The organic layer 312 is provided on the TFT layer 311. The organiclayer 312 includes an organic EL light-emitting element 312 a disposedin each pixel PX. The organic EL light-emitting element 312 a has, forexample, a laminated structure in which an anode, a hole injectionlayer, a hole transport layer, a light-emitting layer, an electrontransport layer, an electron injection layer, and a cathode arelaminated. In the case of the top emission type, the anode is a metalelectrode and the cathode is a transparent conductive film made of ITO(Indium Tin Oxide) or the like. Further, in the organic layer 312,separation walls 312 b for separating organic EL light-emitting elements312 a are provided between pixels PX.

The color filter layer 313 is provided on the organic layer 312. Thecolor filter layer 313 includes color filters 313 a for performing colordisplaying. That is, in each pixel PX, a resin layer colored in R (red),G (green), or B (blue) is provided as the color filter 313 a. When whitelight emitted from the organic layer 312 passes through the colorfilters 313 a, the white light is converted into light having RGBcolors. Note that in the case of a three-color system in which organicEL light-emitting elements capable of emitting each color of RGB areprovided in the organic layer 312, the color filter layer 313 may beunnecessary.

The sealing substrate 314 is provided on the color filter layer 313. Thesealing substrate 314 is a transparent substrate such as a glasssubstrate and is provided to prevent deterioration of the organic ELlight-emitting elements of the organic layer 312.

Electric currents flowing through the organic EL light-emitting elements312 a of the organic layer 312 are changed by display signals suppliedto the pixel circuits. Therefore, it is possible to control an amount oflight emitted in each pixel PX by supplying a display signalcorresponding to a display image to each pixel PX. As a result, it ispossible to display a desired image.

In an active matrix display device such as an organic EL display, onepixel PX is provided with one or more TFTs (for example, a switching TFTand a driving TFT). Then, the TFT of each pixel PX is provided with asemiconductor layer having a source region, a channel region, and adrain region. The polysilicon film according to the present embodimentis suitable for a semiconductor layer of a TFT. That is, by using thepolysilicon film manufactured by the above manufacturing method for asemiconductor layer of a TFT array substrate, it is possible to suppressin-plane ununiformity which is the TFT characteristics. Thus, it ispossible to manufacture a display device having an excellent displaycharacteristic with high productivity.

(Manufacturing Method of Semiconductor Device)

A manufacturing method of a semiconductor device using the ELA apparatusaccording to the present embodiment is suitable for manufacturing a TFTarray substrate. The manufacturing method of a semiconductor devicehaving a TFT is described with reference to FIGS. 17 to 24. FIGS. 17 to24 are cross-sectional views showing processes for manufacturing asemiconductor device. In the following description, a manufacturingmethod of a semiconductor device having an inverted staggered TFT isdescribed.

First, as shown in FIG. 17, a gate electrode 402 is formed on a glasssubstrate 401. Note that, the glass substrate 401 corresponds to theabove substrate 100. As the gate electrode 402, for example, a metalthin film containing aluminium can be used. A metal thin film is formedon the glass substrate 401 by a sputtering method or a depositionmethod. Then, the metal thin film is patterned by photolithography toform the gate electrode 402. In a photolithography method, processing,such as resist coating, exposure, developing, etching, and resiststripping, is performed. Note that, various types of wiring may beformed in the same process as the patterning of the gate electrode 402.

Next, a gate insulating film 403 is formed on the gate electrode 402 asshown in FIG. 18. The gate insulating film 403 is formed so as to coverthe gate electrode 402. Then, an amorphous silicon film 404 is formed onthe gate insulating film 403 as shown in FIG. 19. The amorphous siliconfilm 404 is arranged so as to overlap the gate electrode 402 interposingthe gate insulating film 403.

The gate insulating film 403 is a silicon nitride film (SiN_(x)) or asilicon oxide film (SiO₂ film), or a lamination film thereof, or thelike. Specifically, the gate insulating film 403 and the amorphoussilicon film 404 are continuously formed by a chemical vapor deposition(CVD) method.

Then, the amorphous silicon film 404 is irradiated with the laser beamL1 to form a polysilicon film 405 as shown in FIG. 20. That is, theamorphous silicon film 404 is crystallized by the ELA apparatus 1 shownin FIG. 1 and the like. The polysilicon film 405 with siliconcrystallized is thereby formed on the gate insulating film 403. Thepolysilicon film 405 corresponds to the above polysilicon film 101 b.

At this time, the polysilicon film 405 is inspected by the inspectionmethod according to the present embodiment. When the polysilicon film405 does not meet a predetermined criterion, the polysilicon film 405 isirradiated with a laser beam again. Thus, it is possible to furtheruniformize the characteristic of the polysilicon film 405. Since thein-plane ununiformity can be suppressed, it is possible to manufacture adisplay device having an excellent display characteristic with highproductivity.

Note that, although not shown, the polysilicon film 405 is pattered by aphotolithography method. In addition, impurities may be introduced intothe polysilicon film 405 by an ion implantation method or the like.

Then, an interlayer insulating film 406 is formed on the polysiliconfilm 405 as shown in FIG. 21. The interlayer insulating film 406 isprovided with contact holes 406 a for exposing the polysilicon film 405.

The interlayer insulating film 406 is a silicon nitride film (SiN_(x))or a silicon oxide film (SiO₂ film), or a lamination film thereof, orthe like. Specifically, the interlayer insulating film 406 is formed bya chemical vapor deposition (CVD) method. Then, the interlayerinsulating film 406 is patterned by a photolithography method to formthe contact holes 406 a.

Next, a source electrode 407 a and a drain electrode 407 b are formed onthe interlayer insulating film 406 as shown in FIG. 22. The sourceelectrode 407 a and the drain electrode 407 b are formed so as to coverthe contact holes 406 a. That is, the source electrode 407 a and thedrain electrode 407 b are formed from the inside of the contact holes406 a over the interlayer insulating film 406. Thus, the sourceelectrode 407 a and the drain electrode 407 b are electrically connectedto the polysilicon film 405 though the contact holes 406 a.

Accordingly, a TFT 410 is formed. The TFT 410 corresponds to the aboveTFT 311 a. The region overlapping the gate electrode 402 in thepolysilicon film 405 is a channel region 405 c. The source electrode 407a side of the polysilicon film 405 from the channel region 405 c is asource region 405 a, and the drain electrode 407 b side is a drainregion 405 b.

The source electrode 407 a and the drain electrode 407 b are formed of ametal thin film containing aluminium. A metal thin film is formed on theinterlayer insulating film 406 by a sputtering method or a depositionmethod. Then, the metal thin film is patterned by photolithography toform the source electrode 407 a and the drain electrode 407 b. Notethat, various types of wiring may be formed in the same process as thepatterning of the source electrode 407 a and the drain electrode 407 b.

Then, a planarization film 408 is formed on the source electrode 407 aand the drain electrode 407 b as shown in FIG. 23. The planarizationfilm 408 is formed so as to cover the source electrode 407 a and thedrain electrode 407 b. The planarization film 408 is provided with acontact hole 408 a for exposing the drain electrode 407 b.

The planarization film 408 is formed of, for example, a photosensitiveresin film. A photosensitive resin film is coated on the sourceelectrode 407 a and the drain electrode 407 b, and exposed anddeveloped. Accordingly, it is possible to pattern the planarization film408 having the contact hole 408 a.

Then, a pixel electrode 409 is formed on the planarization film 408 asshown in FIG. 24. The pixel electrode 409 is formed so as to cover thecontact hole 408 a. That is, the pixel electrode 409 is formed from theinside of the contact hole 408 a over the planarization film 408. Thus,the pixel electrode 409 is electrically connected to the drain electrode407 b through the contact hole 408 a.

The pixel electrode 409 is formed of a transparent conductive film or ametal thin film containing aluminium. A conductive film (a transparentconductive film or a metal thin film) is formed on the planarizationfilm 408 by a sputtering method. Then, the conductive film is patternedby the photolithography method. The pixel electrode 409 is therebyformed on the planarization film 408. In the case of a driving TFT of anorganic EL display, the organic EL light emitting device 312 a, thecolor filter (CF) 313 a, and the like as shown FIG. 16 are formed on thepixel electrode 409. Note that, in the case of a top-emission typeorganic EL display, the pixel electrode 409 is formed of a metal thinfilm containing aluminium or silver which have a high reflectance. Inthe case of a bottom-emission type organic EL display, the pixelelectrode 409 is formed of a transparent conductive film such as ITO.

The processes for manufacturing an inverted staggered TFT has beendescribed. The manufacturing method according to the present embodimentmay be applied to manufacture of an inverted staggered TFT. It isobvious that the manufacturing method of a TFT is not limited to a TFTfor an organic EL display and can be applied to manufacture of a TFT fora liquid crystal display (LCD).

In addition, it has been described that the laser annealing apparatusaccording to the present embodiment irradiates an amorphous silicon filmwith a laser beam to form a polysilicon film in the above description,but the laser annealing apparatus may irradiate an amorphous siliconfilm with a laser beam to form a micro-crystal silicon film.Furthermore, a laser beam for performing annealing is not limited toexcimer laser. In addition, the method according to the presentembodiment can be applied to a laser annealing apparatus thatcrystallizes thin films other than a silicon film. That is, as long asthe laser annealing apparatus irradiates an amorphous film with a laserbeam to form a crystallized film, the method according to the presentembodiment can be applied. It is possible for the laser annealingapparatus according to the present embodiment to properly evaluate asubstrate with a crystallized film.

In the above description, it has been described that the manufacturingmethod according to the present embodiment is applied to manufacture ofa TFT array substrate for a display device, such as an organic ELdisplay or a crystal display. However, the method can be applied tomanufacture of a TFT array substrate for other display devices.Furthermore, the manufacturing method according to the presentembodiment can be used for other TFT array substrates except for adisplay device. For example, the semiconductor device according to thepresent embodiment may be used for a TFT array substrate for a flatpanel detector such as an X-ray image sensor. It is possible tomanufacture a TFT array substrate having a uniform semiconductor layercharacteristic with high productivity.

(Determination Method of Optimized Energy Density)

With reference to FIGS. 25 and 26, a method for determining an optimizedenergy density (OED) of the laser beam L1 with which a substrate is tobe irradiated is described. FIG. 25 is a flowchart showing a method fordetermining the OED. FIG. 26 is a schematic diagram for explainingregions of a substrate in the method for determining the OED.

Here, the substrate 100 is divided into a plurality of regions in the Xdirection. As shown in FIG. 26, the divided regions are referred to as aregion Xn−1, a region Xn, a region Xn+1, a region Xn+2, and the like.Note that, the substrate 100 is irradiated with the laser beam L1 andthe probe beam L2 in the order of the region Xn−1, the region Xn, theregion Xn+1, and the region Xn+2. Thus, after the transmittance at theregion Xn−1 is measured, the transmittance at the region Xn is measured.

At the region Xn−1, the region Xn, the region Xn+1, and the region Xn+2,the measured transmittances are respectively referred to as atransmittance Tn−1, a transmittance Tn, a transmittance Tn+1, and atransmittance Tn+2. At each region, a plurality of detection values ofthe transmittance is acquired. For example, the transmittance Tncontains a plurality of detection values. Then, the standard deviationof the detection values of the transmittance Tn−1 is referred to as astandard deviation σn−1. The standard deviations of the detection valuesof the transmittance Tn, the transmittance Tn+1, and the transmittanceTn+2 are respectively referred to as a standard deviation an, a standarddeviation σn+1, and a standard deviation αn+2.

First, the processing apparatus 26 calculates the standard deviationσn−1 at the region Xn−1 (S21). Then, the processing apparatus 26compares the standard deviation σn−1 with a threshold σth of thestandard deviation (S22). When the standard deviation σn−1 is greaterthan the threshold σth, the irradiation intensity of the laser beam L1(energy density) is changed (S23). That is, a laser beam source 11increases or lowers the output. When the standard deviation σn−1 isequal to or less than the threshold σth, the irradiation intensity ofthe laser beam L1 is maintained (S24).

Next, the processing apparatus 26 calculates the standard deviation σnat the region Xn (S25). Then, the processing apparatus 26 compares thestandard deviation σn with the threshold σth of the standard deviation(S26). When the standard deviation σn is greater than the threshold σth,the irradiation intensity of the laser beam L1 is changed (S27). Thatis, the laser beam source 11 increases or lowers the output. The outputof a probe beam source 21 is determined to be increased or lowered inS27 based on the comparison result of the standard deviation σn with thestandard deviation σn−1t. Then, the calculation n=n+1 is performed, thatis, n is incremented, and the processing from S21 is consecutivelyperformed. When the standard deviation σn is equal to or less than thethreshold σth, the irradiation intensity of the laser beam L1 ismaintained (S28).

It is thereby possible to determine the OED of the laser beam L1. Inaddition, while the substrate 100 is being irradiated with the laserbeam L1, the photodetector 25 detects the probe beam L3. Thus, it ispossible to optimize the energy density of the laser beam L1 in realtime. That is, when the standard deviation of the transmittance isgreater than the threshold σth, the laser beam source 11 changes theirradiation intensity of the laser beam L1. Accordingly, it is possibleto reduce the standard deviation of the transmittance at the nextregion. Thus, it is possible to form a high-quality polysilicon film.

Third Embodiment

An ELA apparatus 500 according to a third embodiment is described withreference to FIGS. 27 and 28. FIG. 27 is a side view schematicallyshowing a configuration of the ELA apparatus 500, and FIG. 28 is a planview. As shown in FIG. 27, the ELA apparatus 500 includes a mirror 512,a projection lens 513, a probe beam source 521, a lens 523, a condenserlens 524, a photodetector 525, a door valve 543, a chamber 550, asurface plate 556, a drive mechanism 557, a suction stage 558, and apusher pin 559.

In the present embodiment, the arrangement of the optical system for aprobe beam, specifically, the arrangement of the probe beam source 521and the photodetector 525 is different from that in the first and secondembodiments. When a conveying robot 504 carries a substrate 100 out ofthe ELA apparatus 500, an inspection with a probe beam is performed.That is, after annealing treatment with a laser beam L1 is finished, aninspection with a probe beam L2 is performed. In addition, the suctionstage 558 instead of the gas-floating unit 43 described in the secondembodiment holds the substrate 100 in the present embodiment. Theconfiguration and processing except for these points are similar to theELA apparatus 500 in the first and second embodiments, and thedescription is omitted. For example, the optical system for irradiatingthe substrate 100 with the laser beam L1 is similar to that in the firstembodiment. In addition, the inspection method with a probe beam is alsosimilar to that in the first and second embodiments, and the descriptionis omitted.

The ELA apparatus 500 includes a treatment chamber 550 surrounding atreatment room 541. The inside of the treatment chamber 550 is thetreatment room 541. The treatment room 541 is in inert gas atmosphere,for example, nitrogen gas or the like. A carrying-out port 541 b isprovided at a side wall 551 of the treatment chamber 550. Thecarrying-out port 541 b is provided at the end portion of the treatmentchamber 550 at the +X side. Then, the conveying robot 504 is disposedoutside the treatment chamber 550. The conveying robot 504 includes arobot hand 505 capable of entering the treatment room 541 through thecarrying-out port 541 b.

The conveying robot 504 carries the substrate 100 at a carrying-outposition out through the carrying-out port 541 b. That is, the robothand 505 enters the treatment room 541 from the carrying-out port 541 band takes out the substrate 100 subjected to the treatment from thetreatment room 541. As shown in FIG. 28, the robot hand 505 moves thesubstrate 100 in the +X direction, and the substrate 100 is carried outof the treatment room 541 through the carrying-out port 541 b. Theconveying robot 504 carries the carried-out substrate 100 in a cassette.

Note that, the carrying-out port 541 b may be used as a carrying-inport. That is, the conveying robot 504 may carry the substrate 100before the treatment through the carrying-out port 541 b. Alternatively,a carrying-in port separately from the carrying-out port 541 b may beprovided to the treatment chamber 550. The carrying-out port 541 b isprovided with the door valve 543. The door valve 543 is opened at thetime of carrying the substrate 100 out or the like, and the door valve543 is closed at the time of the irradiation with the laser beam L1.

The surface plate 556, the drive mechanism 557, and the suction stage558 are provided in the treatment room 541. The surface plate 556 isfixed in the treatment chamber 550. The suction stage 558 is attached tothe surface plate 556 through the drive mechanism 557. As shown in FIG.28, the drive mechanism 557 includes an X shaft 557X that moves thesuction stage 558 in the X direction and a shaft 557Y that moves thesuction stage 558 in the Y direction. As described in the firstembodiment, the laser beam L1 is a line beam having its longitudinaldirection in the Y direction on the substrate 100. The drive mechanism557 moves the suction stage 558 in the X direction. Accordingly, whilethe suction stage 558 is moving the substrate 100 along a conveyingpath, the substrate 100 is irradiated with the laser beam L1. Inaddition, the drive mechanism 557 may have a 0 shaft that rotates thesuction stage 558 about the Z axis.

The suction stage 558 sucks and holds the substrate 100. The suctionstage 558 is provided with the pusher pin 559 for carrying the substrate100 in and out. The pusher pin 559 is provided so as to be raised andlowered. When the substrate 100 is carried in or out, the pusher pin 559is raised to transfer the substrate 100 to the robot hand 505.

Specifically, when the pusher pin 559 is raised while the substrate 100is on the suction stage 558, a gap is generated between the substrate100 and the suction stage 558. Then, the robot hand 505 enter the gapbetween the substrate 100 and the suction stage 558. When the pusher pin559 is lowered while the robot hand 505 is being under the substrate100, the robot hand 505 holds the substrate 100.

Alternatively, the robot hand 505 conveys the substrate 100 onto thesuction stage 558 while the pusher pin 559 is being lowered. Then, whenthe pusher pin 559 is raised, the pusher pin 559 holds the substrate100. When the pusher pin 559 is lowered while the substrate 100 is beingplaced on the pusher pin 559, the substrate 100 is placed onto thesuction stage 558. Accordingly, the suction stage 558 becomes ready tosuck the substrate 100. The suction stage 558 sucks the substrate 100 atthe time of the irradiation with the laser beam L1. When the irradiationwith the laser beam L1 is finished, the suction stage 558 releases thesuction.

The probe beam source 521, the lens 523, the condenser lens 524, and thephotodetector 525 are further provided in the treatment room 541. Theprobe beam source 521, the lens 523, the condenser lens 524, and thephotodetector 525 are disposed in the vicinity of the side wall 551. Forexample, the probe beam source 521, the lens 523, the condenser lens524, and the photodetector 525 are fixed on the surface at the treatmentroom 541 side of the side wall 551. For example, while the suction stage558 is being stopped at the substrate carrying-out position (the endmostof the +X side), the probe beam source 521 emits the probe beam L2.

The probe beam L2 emitted from a probe beam source L2 is condensed bythe lens 523 and enters the substrate 100. During the robot hand 505conveys the substrate 100, a polysilicon film 101 b is irradiated withthe probe beam L2 outside the suction stage 558. A probe beam L3transmitted through the substrate 100 is condensed by the condenser lens524 on the photodetector 525. The photodetector 525 outputs detectionsignals to a processing apparatus (the illustration is omitted) asdescribed above.

When the robot hand 505 carries the substrate 100 out through thecarrying-out port 541 b to the outside of the treatment room 541, aninspection with the probe beam L2 can be performed. The robot hand 505carries the substrate 100 on the suction stage 558 out, and theirradiation position of the probe beam L2 is changed toward the +Xdirection. During the robot hand 505 carries the substrate 100 out, thesubstrate 100 passes between the lens 523 and the condenser lens 524.The probe beam L2 from the probe beam source 521 is condensed by thelens 523 on the substrate 100. The probe beam L2 forms an illuminationregion P2 outside the suction stage 558 (see FIG. 28). Note that, theillumination region P2 of the probe beam L2 has a linear shape extendingin the Y direction, but may have a point-like shape.

The probe beam L3 having passed through the polysilicon film 101 b ofthe substrate 100 is condensed by the condenser lens 524 on thephotodetector 525. During the robot hand 505 carries the substrate 100out, the photodetector 525 detects the probe beam L3. That is, the robothand 505 moves the substrate 100 in the +X direction in order for therobot hand 505 to carry the substrate 100 out through the carrying-outport 541 b. While the substrate 100 is being moved in the +X direction,the photodetector 525 detects the probe beam L3. It is thereby possibleto measure the transmittance of the polysilicon film 101 b of thesubstrate 100 in an inspection line IL as shown in FIG. 28. Note that,since the robot hand 505 moves the substrate 100 in the +X direction,the inspection line IL has a belt-like shape or a line shape having itslongitudinal direction in the X direction.

The annealing laser beam L1 forms a linear irradiation region P1 havingits longitudinal direction in the Y direction (see FIG. 3). On the otherhand, the robot hand 505 moves the substrate 100 in the X direction.Thus, at the time of the inspection with a probe beam, the substrate 100is scanned along the latitudinal direction of the irradiation region P1.It is thereby possible to properly evaluate shot unevenness.

Unlike the gas-floating unit, it can be difficult for the suction stage558 to be provided with the optical path of a probe beam. Although thissuction stage 558 is used, it is possible for the photodetector 525 todetect the probe beam L3 transmitted through the substrate 100 with theconfiguration in the present embodiment. Thus, it is possible toproperly inspect the substrate 100. When the substrate 100 is determinedto be abnormal based on the standard deviation or the average value ofthe detection values, the substrate 100 is carried in the ELA apparatus500 and re-irradiated with the laser beam L1. For example, the portionhaving shot unevenness or the entire substrate 100 may be re-irradiatedwith the laser beam L1. Accordingly, it is possible to improve theyield.

The lens 523 forms the illumination region P2 of the probe beam L2 atthe X position between the carrying-out port 541 b and the suction stage558. In the substrate conveying process by the robot hand 505, thesubstrate 100 is moved for a longer distance than the substrate 100. Inthe X direction in which the substrate 100 is conveyed, the inspectionline IL is formed over the entire substrate 100. By evaluating thetransmittance in the inspection line IL, it is possible to evaluate thecrystalline state of the polysilicon film 101 b. In addition, since theinspection can be performed in the substrate conveying process, it isunnecessary to convey the substrate 100 only for performing theinspection. Accordingly, it is possible to prevent the increase in tacttime. Furthermore, the probe beam source 521, the lens 523, thecondenser lens 524, and the photodetector 525 are attached in thevicinity of the side wall 551. Thus, it is possible to prevent a spacefor providing an optical system from increasing.

In addition, two illumination regions P2 of the probe beam L2 are formedon the substrate 100 as shown in FIG. 28 in the present embodiment. Thatis, the substrate 100 is irradiated simultaneously with the two probebeams L2 separated in the Y direction. Accordingly, it is possible tosimultaneously measure the transmittances of the two portions of thesubstrate 100. It is thereby possible to more reliably performevaluation.

For example, when particles are attached to a substrate, abnormal valuesindicating that the transmittance is greatly lowered can be detected atthe points of particles. When such abnormal values are detected, thestandard deviation of the detection values is greatly affected. However,it is difficult to determine whether the abnormal values are caused byparticles or by the crystalline state. Thus, by irradiating thesubstrate with the two or more separated probe beams L2 as described inthe present embodiment, it is possible to eliminate the influence of theabnormal values caused by particles. That is, when one abnormal value atthe same X position is detected, the abnormal value is determined to becaused by particles, or when abnormal values are detected at twoportions, the abnormal values are determined to be caused by shotunevenness. Thus, by eliminating abnormal values caused by particles tocalculate the standard deviation, it is possible to more reliablyperform evaluation.

Note that, it has been described that the robot hand 505 conveys thesubstrate 100 along the latitudinal direction of the irradiation regionP1 of the laser beam L1 in the above description, but the latitudinaldirection of the irradiation region P1 of the laser beam L1 may not bethe same as the conveying direction of the robot hand 505. For example,before the irradiation with the laser beam L1, the suction stage 558 canrotate the substrate 100 about the Z axis (in the θ direction) by 90°.Alternatively, the robot hand 505 can move the substrate 100 in the Ydirection according to the position of a carrying-out port 541. In suchcases, the latitudinal direction of the irradiation region P1 of thelaser beam L1 is orthogonal to the conveying direction of the robot hand505. That is, the inspection line IL is parallel to the longitudinaldirection of the irradiation region P1 of the laser beam L1.

In this case, scanning unevenness instead of shot unevenness of thelaser beam L1 can be evaluated. Note that, scanning unevenness is notcaused by laser but by an optical system and also referred to as opticsunevenness. Specifically, if particles or the like are attached to theoptical element included in the optical system of the laser beam L1, ashadow appears on a part of the irradiation region P1. Since thedetection light amount is lowered at the position where the shadowappears, an abnormal value is detected. The shadow appears at the sameposition in the irradiation region P1, abnormal values are detectedalong the line parallel to the latitudinal direction of the irradiationregion P1. Thus, abnormal values occur in the line at the same positionregardless of the substrate 100, which indicates that there is scanningunevenness. Note that, in order to both evaluate scanning unevenness andshot unevenness, it is only required to evaluate a substrate irradiatedwith a laser at the suction stage set to 0° and the substrate irradiatedwith a laser at the suction stage rotated by 90°.

Note that, when the robot hand 505 carries the substrate 100 out, thesubstrate 100 can be bent and moved up and down. When the substrate 100is moved up and down, the size of the illumination region P2 on thesubstrate 100 is changed. That is, the illumination region P2 has thesmallest size when the focal point of the probe beam L2 by the lens 523is on the substrate 100, but the size of the illumination region P2becomes larger as the substrate 100 is separated farther from the focalpoint.

FIG. 29 shows the size of the probe beam L2 at the Z position when thefocal point at the Z position is set as 0. FIG. 29 shows a simulationresult when the probe beam L2 having the wavelength of 405 nm and thesize of 4 mm is condensed by the lens 523 of f300 mm. The horizontalaxis indicates a Z position, and the vertical axis indicates the size ofthe probe beam L2. In FIG. 29, the size of the probe beam L2 is about 38μm at the focal point. When the Z position is shifted by ±2 mm, the sizeof the probe beam L2 is 47 μm, and this does not matter practically.That is, if the probe beam L2 having the size of 47 μm passes though thesubstrate 100, the photodetector 525 detects the probe beam L3transmitted through the substrate 100 by the condenser lens 524.

(Optical System for Probe Beam)

Next, a configuration of an optical system for a probe beam in an ELAapparatus according to a third embodiment is described. FIGS. 30 to 32are diagrams showing configurations of optical systems for the probebeam L2. FIGS. 30 to 32 each show an optical system that irradiates thesubstrate 100 with the probe beam L2 and detects the probe beam L3transmitted through the substrate 100.

<Optical System 501>

FIG. 30 is a schematic diagram showing an example of an optical system(referred to as an optical system 501). The optical system 501 includesa probe beam source 521, a one-side expander 526, a lens 523, a mirror522, a mirror 529, a collimation lens 528, a condenser lens 524, and aphotodetector 525.

The probe beam source 521 generates a probe beam L2 having a wavelengthof 405 nm. The probe beam L2 from the probe beam source 521 enters theone-side expander 526. The one-side expander 526 has two lenses andexpands the beam diameter in the Y direction. Note that, the conveyingdirection of the substrate 100 by the robot hand 505 is the X direction.The substrate 100 is irradiated with the probe beam L2 from the one-sideexpander 526 through the lens 523 and the mirror 522. Note that, thelens 523 is a cylindrical lens and condenses the probe beam L2 in the Xdirection. Thus, the probe beam L2 forms, on the substrate 100, a linearillumination region having its longitudinal direction in the Y directionand its latitudinal direction in the X direction.

The probe beam L3 transmitted through the substrate 100 is reflected bythe mirror 529 and enters the collimation lens 528. The collimation lens528 turns the probe beam L3 into a parallel luminous flux. The probebeam L3 having passed through the collimation lens 528 enters thecondenser lens 524. The condenser lens 524 condenses the probe beam L3on the light-receiving surface of the photodetector 525. Thephotodetector 525 is provided with a band-pass filter 525 a. Theband-pass filter 525 a transmits light having a wavelength of 405 nm.Accordingly, it is possible to prevent stray light having a wavelengthother than the wavelength of the probe beam from entering thephotodetector 525.

With the optical system 501, it is possible to properly evaluate thecrystalline state. In addition, the optical system 501 may be providedwith a camera 530 that confirms the focal point of the lens 523. Acamera 30 captures an image of the illumination region of the probe beamL2 and its surroundings. The focal point can be adjusted based on theimage by the camera 530. The camera 530 may be provided only at the timeof installing the optical system 501.

<Optical System 502>

FIG. 31 is a schematic diagram showing another example of an opticalsystem for a probe beam (referred to as an optical system 502). Theoptical system 502 has a configuration for detecting a probe beam havingpassed through the substrate 100 twice. The optical system 502 includesa probe beam source 521, a one-side expander 526, a lens 523, a mirror522, a mirror 531, a collimation lens 532, a condenser lens 533, amirror 534, a mirror 529, a collimation lens 528, a condenser lens 524,and a photodetector 525.

The probe beam source 521 generates a probe beam L2 having a wavelengthof 405 nm. The probe beam L2 from the probe beam source 521 enters theone-side expander 526. The one-side expander 526 has two lenses andexpands the beam diameter in the Y direction. The substrate 100 isirradiated with the probe beam L2 from the one-side expander 526 throughthe lens 523 and the mirror 522. Note that, the lens 523 is acylindrical lens and condenses the probe beam L2 in the X direction.Thus, the probe beam L2 reflected by the mirror 522 forms, on thesubstrate 100, a linear illumination region having its longitudinaldirection in the Y direction and its latitudinal direction in the Xdirection.

The probe beam L2 transmitted through the substrate 100 is reflected bythe mirror 531 and enters the collimation lens 532. The collimation lens532 turns the probe beam L2 into a parallel luminous flux. The probebeam L2 from the collimation lens 532 enters the substrate 100 throughthe condenser lens 533 and the mirror 534. Note that, the condenser lens533 is a cylindrical lens and condenses the probe beam L2 in the Xdirection. Thus, the probe beam L2 reflected by the mirror 534 forms, onthe substrate 100, a linear illumination region having its longitudinaldirection in the Y direction and its latitudinal direction in the Xdirection.

The probe beam L3 transmitted through the substrate 100 is reflected bythe mirror 529 and enters the collimation lens 528. The collimation lens528 turns the probe beam L3 into a parallel luminous flux. The probebeam L3 having passed through the collimation lens 528 enters thecondenser lens 524. The condenser lens 524 condenses the probe beam L3on the light-receiving surface of the photodetector 525. Thephotodetector 525 is provided with a band-pass filter 525 a. Theband-pass filter 525 a transmits light having a wavelength of 405 nm.Accordingly, it is possible to stray light having a wavelength otherthan the wavelength of the probe beam from entering the photodetector525.

In this manner, the photodetector 525 detects the probe beam L3 havingpassed through the polysilicon film 101 b twice in the optical system502. Accordingly, it is possible to emphasize transmittance unevenness.Thus, it is possible to properly evaluate the crystalline state.

The focal point by the lens 523 is shifted from the focal point by thecondenser lens 533 in the Y direction on the substrate 100. That is,when the conveying direction by the robot hand 505 is the X direction,the probe beam L2 has passed through the substrate 100 twice atdifferent Y positions and at the same X position. Accordingly, sinceshot unevenness is emphasized, it is possible to properly evaluate thecrystalline state. Naturally, the optical system 502 may be configuredso that a probe beam passes through the polysilicon film 101 b threetimes or more. For example, a mirror and a lens can be added in orderfor a probe beam to pass through the polysilicon film 101 b three timesor more.

The first and second positions where the probe beam L2 passes throughthe substrate 100 are separated in the Y direction. Thus, it is possibleto reduce the influence of particles. For example, if a particle isattached to the first passing position, the particle is not attached tothe second passing position. Thus, it is possible to reduce theinfluence of particles on lowering the transmittance. Accordingly, it ispossible to properly evaluate the crystalline state.

The optical system 502 may be provided with cameras 530 a and 530 b thatrespectively confirm the focal points of the lens 523 and the condenserlens 533. The cameras 530 a and 530 b each capture an image of theillumination region of the probe beam L2 and its surroundings. The focalpoints can be adjusted based on the images by the cameras 530 a and 530b. The cameras 530 a and 530 b may be provided only at the time ofinstalling the optical system 502.

<Optical System 503>

FIG. 32 is a schematic diagram showing another example of an opticalsystem for a probe beam (referred to as an optical system 503). Theoptical system 503 has a configuration for detecting a probe beam havingpassed through the substrate 100 twice. In addition, the probe beam L2passes through the substrate 100 at the same position twice in anoptical system 303. The optical system 503 includes a probe beam source521, a one-side expander 526, a polarizing plate 536, a lens 523, a beamsplitter 537, a condenser lens 533, a quarter-wavelength plate 538, amirror 539, a collimation lens 528, a condenser lens 524, and aphotodetector 525.

The probe beam source 521 generates a probe beam L2 having a wavelengthof 405 nm. The probe beam L2 from the probe beam source 521 enters theone-side expander 526. The one-side expander 526 expands the beamdiameter in the Y direction. The substrate 100 is irradiated with theprobe beam L2 from the one-side expander 526 through the polarizingplate 536, the lens 523, and the beam splitter 537. The polarizing plate536 turns the probe beam L2 into linearly polarized light along a firstdirection. The beam splitter 537 is, for example, a polarizing beamsplitter, reflects the linearly polarized light along the firstdirection, and transmits linearly polarized light along a seconddirection orthogonal to the first direction. Thus, the beam splitter 537reflects the probe beam L2 toward the substrate 100.

The lens 523 is a cylindrical lens and condenses the probe beam L2 inthe X direction. Accordingly, the probe beam L2 forms, on the substrate100, a linear illumination region having its longitudinal direction inthe Y direction and its latitudinal direction in the X direction.

The probe beam L2 transmitted through the substrate 100 enters thecondenser lens 533 which is a cylindrical lens. The condenser lens 533functions as a collimation lens that turns the probe beam L2 from thesubstrate 100 into a parallel luminous flux. The probe beam L2 from thecondenser lens 533 is reflected by the mirror 539 through thequarter-wavelength plate 538. The mirror 539 is a total reflectionmirror and makes the probe beam L2 transmitted through thequarter-wavelength plate 538 enter the quarter-wavelength plate 538again. Since the probe beam L2 passed through the quarter-wavelengthplate 538 twice, the linearly polarized light is rotated by 90°. Thus,the probe beam L2 directed from the quarter-wavelength plate 538 towardthe substrate 100 is linearly polarized light along the seconddirection.

The probe beam L2 having passed through the quarter-wavelength plate 538twice is condensed by the condenser lens 533 on the substrate 100. Asdescribed above, the probe beam L2 forms, on the substrate 100, a linearillumination region having its longitudinal direction in the Y directionand its latitudinal direction in the X direction. The probe beam L3transmitted through the substrate 100 enters the beam splitter 537. Asdescribed above, the probe beam L3 is linearly polarized light along thesecond direction and transmitted through the beam splitter 537. Theprobe beam L3 transmitted through the beam splitter 537 enters thecollimation lens 528.

The collimation lens 528 turns the probe beam L3 into a parallelluminous flux. The probe beam L3 having passed through the collimationlens 528 enters the condenser lens 524. The condenser lens 524 condensesthe probe beam L3 on the light-receiving surface of the photodetector525. The photodetector 525 is provided with a band-pass filter 525 a.The band-pass filter 525 a transmits light having a wavelength of 405nm. Accordingly, it is possible to stray light having a wavelength otherthan the wavelength of the probe beam from entering the photodetector525.

In this manner, the photodetector 525 detects the probe beam L3 havingpassed through the polysilicon film 101 b twice in the optical system503. Accordingly, it is possible to emphasize transmittance unevenness.In addition, the focal point by the lens 523 and the focal point by thecondenser lens 533 are at the same position on the substrate 100.Accordingly, it is possible to emphasize shot unevenness and to moreproperly evaluate the crystalline state.

Note that, the probe beam L2 has passed through the substrate 100 at thesame position in the optical system 503. The optical system 503 may beprovided with a camera 530 that confirms the focal points of the lens523 and the condenser lens 533. The camera 530 captures an image of theillumination region of the probe beam L2 and its surroundings. The focalpoints can be adjusted based on the image by the camera 530. The camera530 may be provided only at the time of installing the optical system503.

FIG. 33 is a graph showing the average value and the standard deviationof the detection signals acquired by the photodetector 52. FIG. 33 showsa measurement result when the energy density is changed in the rangefrom 400 to 435 mJ/cm² and at a pitch of 5 mJ/cm². When the energydensity is 420 mJ/cm² and 425 mJ/cm², the average values of thedetection signals are low. Thus, the OED is to be either 420 mJ/cm² or425 mJ/cm².

However, the average values at 420 mJ/cm² and 425 mJ/cm² are nearly thesame, and it is difficult to obtain the OED from the average values. Onthe other hand, the standard deviation at 420 mJ/cm² is less than thestandard deviation at 425 mJ/cm². Thus, the OED can be set to 420mJ/cm². In this manner, by using the average values and the standarddeviations of the detection values, it is possible to properly determinethe OED.

The present invention is not limited to the above-described embodiments,various modifications can be made without departing from the spirit andscope of the present invention.

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2016-163693, filed on Aug. 24, 2016 andJapanese patent application No. 2017-112516, filed on Jun. 7, 2017, thedisclosure of which is incorporated herein in its entirety by reference.

REFERENCE SIGNS LIST

-   -   1 Laser annealing apparatus    -   11 Laser beam source    -   12 Mirror    -   13 Projection lens    -   21 Probe beam source    -   22 Mirror    -   23 Lens    -   24 Condenser lens    -   25 Photodetector    -   26 Treatment apparatus    -   100 Substrate    -   101 Silicon film    -   300 Organic EL display    -   310 Substrate    -   311 TFT layer    -   311 a TFT    -   312 Organic layer    -   312 a Organic EL light emitting device    -   312 b Partition wall    -   313 Color filter layer    -   313 a Color filter (CF)    -   314 Sealing substrate    -   401 Glass substrate    -   402 Gate electrode    -   403 Gate insulating film    -   404 Amorphous silicon film    -   405 Polysilicon film    -   406 Interlayer insulating film    -   407 a Source electrode    -   407 b Drain electrode    -   408 Planarization film    -   409 Pixel electrode    -   410 TFT    -   PX Pixel

1-26. (canceled)
 27. A laser annealing apparatus comprising: a laserbeam source configured to emit a laser beam to crystallize an amorphousfilm over a substrate and to form a crystallized film; a projection lensconfigured to condense the laser beam to irradiate the amorphous film; aprobe beam source configured to emit a probe beam; a photodetectorconfigured to detect the probe beam transmitted through the crystallizedfilm; a conveying path configured to convey the substrate to change anirradiation position of the laser beam onto the substrate; and aprocessing unit configured to change an irradiation position of theprobe beam onto the substrate, to calculate a standard deviation ofdetection values of a detection signal output from the photodetector,and to determine a crystalline state of the crystallized film based onthe standard deviation.
 28. The laser annealing apparatus according toclaim 27, wherein the processing unit is configured to: compare thestandard deviation with a threshold; and determine the substrate to benon-defective when the standard deviation is less than the threshold ordetermine the substrate to be defective when the standard deviation isequal to or greater than the threshold.
 29. The laser annealingapparatus according to claim 27, wherein the processing unit configuredto determine the crystalline state based on an average value of thedetection values.
 30. The laser annealing apparatus according to claim27, wherein the projection lens is configured to cause the laser beam toform a linear irradiation region on the amorphous film, and thephotodetector is configured to detect the probe beam having passedthrough the projection lens.
 31. The laser annealing apparatus accordingto claim 27, further comprising: a cylindrical lens configured to causethe probe beam to form a linear illumination region on the crystallizedfilm; and a condenser lens configured to condense the probe beamtransmitted through the crystallized film on the photodetector.
 32. Thelaser annealing apparatus according to claim 27, wherein the conveyingpath is configured to convey the substrate while the substrate is beingirradiated simultaneously with the laser beam and the probe beam. 33.The laser annealing apparatus according to claim 27, wherein theconveying path comprises a gas-floating unit configured to jet gas tothe substrate to float the substrate.
 34. The laser annealing apparatusaccording to claim 27, further comprising a stage configured to hold thesubstrate, wherein the stage is configured to be moved to convey thesubstrate along the conveying path, the laser annealing apparatuscomprises a carrying-out port which a conveying robot that carries thesubstrate out from the stage enters, and the irradiation position of theprobe beam onto the substrate is changed by the conveying robot carryingthe substrate out from the stage.
 35. The laser annealing apparatusaccording to claim 34, wherein the photodetector is configured to detectthe probe beam having passed through the crystallized film twice ormore.
 36. A laser annealing apparatus comprising: a laser beam sourceconfigured to emit a laser beam to crystallize an amorphous film over asubstrate and to form a crystallized film; a projection lens configuredto condense the laser beam to irradiate the amorphous film; a stageconfigured to convey the substrate to change an irradiation position ofthe laser beam onto the substrate; a probe beam source configured toemit a probe beam; a photodetector configured to detect the probe beamtransmitted through the crystallized film outside the stage during aconveying robot takes out the substrate from the stage; and a processingunit configured to determine a crystalline state of the crystallizedfilm based on a detection signal output from the photodetector.